In retail establishments like grocery stores, self-service checkouts have become increasingly popular. In a traditional checkout, an employee of a retail establishment typically scans the items that a customer wants to purchase, bags the items, and assists the customer in paying for the items. By comparison, in a self-service checkout, the customer him or herself scans, bags, and pays for the items, and receives assistance from an employee of the retail establishment only if there is a problem.
Many customers use physical coupons, which are typically pieces of paper that have bar codes on them that when scanned discount the prices of their associated items by given amounts or percentages. In a traditional checkout, the customer hands the employee all his or her coupons, and the employee scans the coupons one at a time and then places the coupons in an envelope or storage container so that the coupons cannot be used again. In a self-service checkout, the customer scans the coupons him or herself, and then is supposed to place the coupons in a secure storage container, or give the coupons to an employee when leaving the retail establishment, so that the coupons cannot be used again.